JP6651990B2 - Method for producing hydraulic composition - Google Patents

Description

  The present invention relates to a method for producing a hydraulic composition.

  Water-soluble cellulose ethers such as hydroxypropylmethylcellulose, which is a type of water-soluble polymer, exhibit a viscosity increase in hydraulic compositions, and are therefore inseparable underwater concrete (separation suppression during casting in water), sprayed concrete ( Widely used in concrete applications such as dust prevention during spraying) and high fluidity concrete (suppression of material separation during casting).

The hydraulic composition is a mixture of a hydraulic substance such as cement, an aggregate such as fine aggregate and coarse aggregate, water, a water reducing agent, and the like, and is generally manufactured in a raw concrete plant.
When producing a hydraulic composition containing a thickener such as the water-soluble cellulose ether in a raw conplant, the addition of the thickener causes adverse effects such as a decrease in the slump value or an increase in the amount of air for the next batch. To achieve this, a ready-mixed concrete composition, which is a mixture of a hydraulic substance, an aggregate, water, a water reducing agent, and the like, is manufactured in advance in a ready-mixed plant, and a thickener is further added at the casting site.

However, when a powdery thickener is added to the ready-mixed concrete composition, a small amount of the thickener is added, so that the desired amount is not added due to scattering at the time of addition, and a sufficient effect as a hydraulic composition is obtained. It is difficult. For this reason, the thickener is usually added as an aqueous solution, but because of its high viscosity, it is difficult to add it at a high concentration.
To compensate for this drawback, at the casting site, for example, a water-soluble cellulose ether is subjected to a crosslinking reaction with glyoxal, and a water-soluble cellulose ether treated so as not to be temporarily dissolved in water is added to the ready-mixed concrete composition. (Non-Patent Document 1). By this method, it became possible to add a water-soluble cellulose ether to the ready-mixed concrete composition without increasing the viscosity at the casting site.

Regarding in-water non-separable concrete and Aska Clean on-site addition method, Shin-Etsu Chemical Co., Ltd. Organic Synthesis Division Cellulose Department, July 2012

However, in the case of the method of Non-Patent Document 1, when the concentration of the water-soluble cellulose ether is 12% by mass or more, the water-soluble cellulose ether is significantly thickened and handling becomes difficult, and addition of a high-concentration aqueous solution is difficult. . Therefore, a large amount of water had to be prepared at the casting site, and a large amount of aqueous cellulose ether solution had to be added to the agitator vehicle. In addition, there was a problem of cost increase accompanying the glyoxal treatment.
For these reasons, a new method that replaces the method using a glyoxal-treated water-soluble cellulose ether has been desired.

  The present invention has been made in view of the above circumstances, even in the case of using a water-soluble cellulose ether that has not been subjected to glyoxal treatment, can suppress the increase in the viscosity of the hydraulic composition, easy handling, and casting site An object of the present invention is to provide a method for producing a hydraulic composition having desired properties even when a small amount of water is added.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, mixed a mixed aqueous solution containing a water-soluble salt composed of a predetermined anionic substance and a water-soluble cellulose ether with a ready-mixed concrete composition at a casting site. By doing so, the present inventors have found that a hydraulic composition having easy properties and a desired property can be obtained even by adding a small amount of water, thereby completing the present invention.

That is, the present invention
1. (A) a water-soluble salt comprising an anionic substance selected from a water reducing agent and a setting retarder, and a mixed aqueous solution containing a water-soluble cellulose ether; and (B) a ready-mixed concrete composition containing a hydraulic substance, aggregate and water. A method for producing a hydraulic composition, characterized by mixing at the casting site,
2. (A) the method for producing a hydraulic composition according to 1, wherein the sodium ion concentration in the mixed aqueous solution is 1,000 to 50,000 ppm;
3. The method for producing a hydraulic composition according to 1 or 2, wherein the water reducing agent is a polycarboxylic acid-based water reducing agent,
4. The method for producing a hydraulic composition according to 1 or 2, wherein the setting retarder is sodium gluconate;
5. The present invention provides a method for producing a hydraulic composition according to any one of 1 to 4, wherein the water-soluble cellulose ether is one or more selected from alkylcellulose, hydroxyalkylcellulose and hydroxyalkylalkylcellulose.

  According to the present invention, a hydraulic composition having a low bleeding rate can be manufactured even with easy handling and addition of a small amount of water at a casting site.

Hereinafter, the present invention will be described specifically.
The method for producing a hydraulic composition of the present invention comprises: (A) a mixed aqueous solution containing a water-soluble salt comprising an anionic substance selected from a water reducing agent and a setting retarder, and a water-soluble cellulose ether; And a ready-mixed concrete composition containing water, aggregate and water at the casting site.

(A) Mixed aqueous solution In the present invention, a mixed aqueous solution containing a water-soluble salt composed of an anionic substance selected from a water reducing agent and a setting retarder, and a water-soluble cellulose ether is used in advance. Thus, a hydraulic composition which is easy to handle and has desired properties can be obtained by adding a small amount of water.
The hydraulic composition of the present invention using such a mixed aqueous solution can be added with a higher concentration of a water-soluble cellulose ether at a casting site than in the case of using a glyoxal-treated water-soluble cellulose ether. . As a result, an amount of water-soluble cellulose ether necessary for obtaining a hydraulic composition having desired properties is added, so that a hydraulic composition having excellent bleeding properties and the like can be obtained.

As the water reducing agent, a polycarboxylic acid-based water reducing agent, a melamine-based water reducing agent, a lignin-based water reducing agent, etc. are used in view of the fact that a water reducing effect can be obtained by suppressing the aggregation of the hydraulic composition in water. be able to.
As the polycarboxylic acid-based water reducing agent, a salt of a polycarboxylic acid-based copolymer is preferable, and specific examples of the polycarboxylic acid-based copolymer include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, An unsaturated mono- or dicarboxylic acid selected from itaconic acid and citraconic acid; and an unsaturated monomer selected from polyalkylene glycol mono (meth) acrylate, styrene and a compound obtained by adding 1 to 100 moles of alkylene oxide to unsaturated alcohol. And a copolymer of
Specific examples of the melamine-based water reducing agent include a salt of a melamine sulfonic acid formalin condensate, a salt of a melamine sulfonate condensate, and a salt of a melamine sulfonate polyol condensate.
Specific examples of lignin-based water reducing agents include lignin sulfonates.
In addition, as a salt of each of the above compounds, a sodium salt is preferable from the viewpoint of solubility.
Among the various water reducing agents described above, it is particularly preferable to use a polycarboxylic acid-based water reducing agent from the viewpoint of water reducing effect, fluidity and fluidity retention.

These water reducing agents are added in the form of an aqueous solution, and the solid content concentration is 5 to 50% by mass.
The content of the aqueous solution of the water reducing agent in the mixed aqueous solution is preferably 50.0 to 99.0% by mass, more preferably 60.0 to 90.0% by mass, and still more preferably 70.0 to 88.0% by mass. The total amount of the aqueous solution of the water reducing agent and the water-soluble cellulose ether described below is preferably 100% by mass.

The setting retarder has a function of delaying the setting time of the hydraulic composition, and is used for the purpose of suppressing the occurrence of a cold joint at the time of placing concrete on a large scale.
Specific examples of the setting retarder include oxycarboxylic acid salts such as gluconic acid and glucoheptonic acid, keto acid salts, silicofluoride salts, phosphates, borates and the like. Of these, oxycarboxylates are preferred from the viewpoint of setting retardation.
The setting retarder is also added in the form of an aqueous solution as in the case of the water reducing agent, and its solid content concentration is 10 to 50% by mass. However, the setting retarder is added as a highly concentrated (20 to 40% by mass) aqueous solution as much as possible. Is preferred.
The content of the setting retarder in the mixed aqueous solution is, for example, preferably 50.0 to 99.0% by mass, more preferably 60.0 to 90.% when a 30% by mass aqueous solution of sodium gluconate is used. 0 mass%, more preferably 70.0 to 88.0 mass%.

  Water-soluble cellulose ethers are nonionic, and alkyl celluloses such as methylcellulose and ethylcellulose in that they can suppress material separation of hydraulic compositions, improve durability by reducing bleeding, and reduce variations in strength and quality; Hydroxyalkyl cellulose such as hydroxypropylcellulose and hydroxyethylcellulose; hydroxyalkylalkylcellulose such as hydroxypropylmethylcellulose and hydroxyethylethylcellulose are preferably used.

More specifically, as the alkylcellulose, DS is preferably 1.0 to 2.2, more preferably 1.2 to 2.0 methylcellulose, and DS is preferably 1.0 to 2.2, more preferably. Is 1.2 to 2.0 ethyl cellulose.
As the hydroxyalkyl cellulose, MS is preferably 0.1 to 3.0, more preferably 0.5 to 2.8 hydroxyethyl cellulose, and MS is preferably 0.05 to 3.3, more preferably 0.1. And 3.0-hydroxypropylcellulose.
As the hydroxyalkylalkyl cellulose, DS is preferably 1.0 to 2.2, more preferably 1.2 to 2.0, MS is preferably 0.05 to 0.6, and more preferably 0.10 to 0. Hydroxyethyl methylcellulose, DS is preferably 1.0 to 2.2, more preferably 1.2 to 2.0, MS is preferably 0.05 to 0.6, more preferably 0.10 to 0. Hydroxypropylmethylcellulose, DS is preferably 1.0 to 2.2, more preferably 1.2 to 2.0, MS is preferably 0.05 to 0.6, and more preferably 0.10 to 0. .5 hydroxyethylethylcellulose.

Note that DS represents the degree of substitution, which is the number of alkoxy groups present per glucose ring unit of cellulose, and MS represents the molar substitution, which is the molar substitution of glucose ring unit of cellulose. It is the average number of moles of hydroxyalkoxy groups added per unit.
The degree of substitution of these alkyl groups and the number of moles of substitution of hydroxyalkyl groups can be measured by a method for analyzing the degree of substitution of hypromellose (hydroxypropylmethylcellulose) described in the 16th revised Japanese Pharmacopoeia.

The aqueous solution viscosity of 2% by mass or 1% by mass of the water-soluble cellulose ether of the present invention at 20 ° C is preferably 100 (at 20 rpm of a BH viscometer) from the viewpoint of imparting a predetermined viscosity to the hydraulic composition. 2% by mass) to 30,000 (1% by mass) mPa · s, more preferably 400 (2% by mass) to 25,000 (1% by mass) mPa · s, and still more preferably 500 (2% by mass) to 20%. 2,000 mPa · s (1% by mass).
In addition, the viscosity of the water-soluble cellulose ether is a value measured with a 2% by mass aqueous solution when the viscosity is 50,000 mPa · s or less, and is a value measured with a 1% by mass aqueous solution when the viscosity exceeds 2% by mass.
The content of the water-soluble cellulose ether in the mixed aqueous solution is preferably 0.1 to 40% by mass, more preferably 0.5 to 35% by mass, and still more preferably 1 to 30% by mass.

In the present invention, the sodium ion concentration of the water-soluble salt is preferably 1,000 to 50,000 ppm, more preferably 2,000 to 40,000 ppm, and still more preferably 5,000 to 20,000 ppm.
When the sodium ion concentration of the water-soluble salt is lower than 1,000 ppm, the water-soluble cellulose ether dissolves without salting out, so that the viscosity of the mixed aqueous solution increases, and water having a predetermined property is obtained by adding a smaller amount of water. In some cases, a hard composition cannot be obtained. On the other hand, when the sodium ion concentration of the water-soluble salts is higher than 50,000 ppm, the sodium ion concentration in the hydraulic composition increases, and the reinforcing bar may be easily rusted.

Measurement of sodium ions in water-soluble salt, the water soluble salts and diluted to a concentration of 1 / 10,000-fold with pure water, and filtered through 0.2μm filter, the resulting filtrate ion chromatography Measure by graph. The analyzer used for the measurement is, for example, an ion chromatograph, DIONEX ICS-1600 (manufactured by Thermo Fisher Scientific Co., Ltd.), and CG14 (guard) + CS14 (main) (the above is referred to as Thermo Fisher Scientific) as a column. FIPS Co., Ltd.) can be measured using CERS-500-4 mm (manufactured by Thermo Fisher Scientific KK) as a suppressor and 10 mM metasulfonic acid as an eluent.

In the present invention, when the foaming of the mixed aqueous solution and the air amount of the hydraulic composition exceed a predetermined air amount (for example, 6%), an antifoaming agent may be added to the mixed aqueous solution.
The defoaming agent is not particularly limited, but oxyalkylene-based, silicone-based, alcohol-based, mineral oil-based, fatty acid-based, and fatty acid ester-based defoaming agents are preferable in terms of easy control of the amount of air. It is preferably used.

  Specific examples of the oxyalkylene-based antifoaming agent include polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adduct; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, and polyoxyethylene polyoxyethylene. (Oxy) oxyalkylene alkyl ethers such as oxypropylene 2-ethylhexyl ether, higher alcohols having 8 or more carbon atoms and oxyethyleneoxypropylene adducts to secondary alcohols having 12 to 14 carbon atoms; polyoxypropylene phenyl ether; (Poly) oxyalkylene (alkyl) aryl ethers such as polyoxyethylene nonylphenyl ether; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl Acetylene ethers obtained by addition-polymerizing an alkylene oxide to acetylene alcohol such as 3-hexyne-2,5-diol, 3-methyl-1-butyn-3-ol; diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearin (Poly) oxyalkylene fatty acid esters such as acid esters; (poly) oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan trioleate; sodium polyoxypropylene methyl ether sulfate, poly (Poly) oxyalkylenealkyl (aryl) ether sulfates such as sodium oxyethylene dodecylphenol ether sulfate; Shi ethylene stearyl phosphate ester of (poly) oxyalkylene alkyl phosphoric acid esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; polyoxyalkylene amides.

Specific examples of the silicone-based antifoaming agent include dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil, and the like.
Specific examples of the alcohol-based antifoaming agent include octyl alcohol, 2-ethylhexyl alcohol, hexadecyl alcohol, acetylene alcohol, and glycols.
Specific examples of the mineral oil-based antifoaming agent include kerosene and liquid paraffin.
Specific examples of the fatty acid-based antifoaming agent include oleic acid, stearic acid, and alkylene oxide adducts thereof.
Specific examples of the fatty acid ester-based antifoaming agent include glycerin monoricinoleate, alkenyl succinic acid derivatives, sorbitol monolaurate, sorbitol trioleate, and natural wax.
Among these antifoaming agents, oxyalkylene-based antifoaming agents, mineral oil-based antifoaming agents, and fatty acid ester-based antifoaming agents are particularly preferable in terms of dispersion stability of the mixed aqueous solution.
The content of the antifoaming agent in the mixed aqueous solution is preferably 0.001 to 16% by mass, and more preferably 0.002 to 10% by mass.

(B) Ready-mixed concrete composition The hydraulic composition of the present invention is obtained by mixing (A) the mixed aqueous solution and (B) a ready-mixed concrete composition containing a hydraulic substance, aggregate and water at a casting site. Is obtained by
The amount of the (A) mixed aqueous solution added to the hydraulic composition is determined from the viewpoints of securing the amount of water necessary for the fluidity of the ready-mixed concrete composition (B) produced in the ready-mixed plant and the mixing property at the casting site. B) The amount is preferably 1 to 4 kg, more preferably 1.5 to 3.5 kg, and still more preferably 2 to ³ kg per m ³ of the ready-mixed concrete composition.

Examples of the hydraulic substance include cement, and specific examples thereof include ordinary Portland cement, early-strength Portland cement, moderate heat Portland cement, blast furnace cement, silica cement, fly ash cement, alumina cement, and ultra-high-strength Portland cement. And the like.
The addition amount of hydraulic substance in the hydraulic composition, from the viewpoint of compressive strength or fluidity, the hydraulic composition 1 m ³ per preferably 100～600Kg, more preferably 200～500Kg, more preferably at 220~400kg is there.

The aggregate contains coarse aggregate and fine aggregate.
As the coarse aggregate, river gravel, mountain gravel, land gravel, crushed stone and the like are preferable, and the particle size is preferably 40 mm or less, more preferably 25 mm or less.
As the fine aggregate, river sand, mountain sand, land sand, silica sand, crushed sand, and the like are preferable, and the particle size is preferably 10 mm or less, more preferably 5 mm or less.
Amount of aggregate in the hydraulic composition (total amount of coarse aggregate and fine aggregate), from the viewpoint of compressive strength or fluidity, the hydraulic composition 1 m ³ per preferably 1,200～2, 000 kg, more preferably 1,500 to 1,900 kg. The ratio of the fine aggregate in the aggregate is represented by the fine aggregate ratio, and is preferably 30 to 55% by mass, and more preferably 35 to 50% by mass.
The addition amount of water in the hydraulic composition, the hydraulic composition 1 m ³ per preferably 120～240Kg, more preferably 140～200Kg, more preferably 150～175Kg.

Further, in the hydraulic composition of the present invention, an AE agent can be used as needed for the purpose of securing a predetermined amount of air and obtaining durability of concrete.
As the AE agent, an anionic surfactant system, a cationic surfactant system, a nonionic surfactant system, an amphoteric surfactant system or the like is used.
Specific examples of the anionic surfactant-based AE agent include a carboxylic acid type, a sulfate ester type, a sulfonic acid type, and a phosphate ester type.
Specific examples of the cationic surfactant type AE agent include an amine salt type, a primary amine salt type, a secondary amine salt type, a tertiary amine salt type, and a quaternary amine salt type.
Specific examples of the nonionic surfactant-based AE agent include ester type, ester ether type, ether type, alkanolamide type and the like.
Specific examples of the amphoteric surfactant AE agent include an amino acid type and a sulfobetaine type.
Among these AE agents, it is preferable to use an anionic surfactant-based AE agent in the hydraulic composition of the present invention from the viewpoint of air entrainment.
The amount of the AE agent added is preferably 0.001 to 0.01% by mass based on the hydraulic substance.

Further, in the hydraulic composition of the present invention, alkylene oxide may be added as a drying shrinkage reducing agent, if necessary, for the purpose of preventing shrinkage cracking due to curing and drying, cracking due to temperature stress due to heat of hydration reaction of cement, and the like. , Polyether, polyglycol, etc., and (3CaO.3Al ₂ O ₃ .CaSO ₄ ), CaO, etc. can be used in a usual amount as an expanding material.
The amount of the drying shrinkage reducing agent is preferably 0.1 to 10% by mass based on the hydraulic composition, and the amount of the expanding material is preferably 0.1 to 10% by mass based on the hydraulic composition. 10% by mass.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

A. Preparation of mixed aqueous solution [Preparation Examples A1 to A5, Comparative Preparation Examples A1 and A2]
The following water reducing agent or setting retarder, and water-soluble cellulose ether were blended in the mixing ratio shown in Table 1, and mixed at 5,000 rpm for 1 minute using a homomixer (manufactured by HM-310 AS ONE). To prepare a mixed aqueous solution.
The content of the water-soluble cellulose ether in the comparative mixed aqueous solution was the maximum content that can be handled.

<Material used>
(1) Water reducing agent, Tupole EX60 (WRA-1)
Takemoto Oil & Fat Co., Ltd., polycarboxylic acid-based water reducing agent, solid content concentration 12.3% by mass, sodium ion concentration 8,600 ppm
・ Tupole EX60 concentrate (concentrated about 1.5 times under reduced pressure) (WRA-2)
Takemoto Oil & Fat Co., Ltd., polycarboxylic acid-based water reducing agent, solid content concentration 18.0% by mass, sodium ion concentration 12,500 ppm
(2) Setting retarder
・ Sodium gluconate (G), solid content concentration 23.1%, sodium ion concentration 24,800 ppm, reagent primary (3) water-soluble cellulose ether ・ hydroxypropyl methylcellulose (HPMC-1)
DS: 1.4, MS: 0.2, 2% by mass aqueous solution viscosity at 20 ° C .: 400 mPa · s
・ Hydroxypropyl methylcellulose (HPMC-2)
DS: 1.8, MS: 0.2, 2% by mass aqueous solution viscosity at 20 ° C .: 390 mPa · s
・ Hydroxyethyl methylcellulose (HEMC)
DS: 1.5, MS: 0.3, 2% by mass aqueous solution viscosity at 20 ° C .: 410 mPa · s
・ Hydroxypropyl methylcellulose (HPMC-3)
DS: 1.4, MS: 0.2, 2% by mass aqueous solution viscosity at 20 ° C .: 430 mPa · s), glyoxal treatment (2% by mass based on HPMC)

B. Preparation of ready-mixed concrete composition [Preparation Example B1]
A ready-mixed concrete composition was prepared by mixing the following cement, fine aggregate, coarse aggregate, AE agent and water in the mixing ratio shown in Table 2.
Specifically, cement, fine aggregate, and coarse aggregate were put into a 60-liter forced biaxial kneading mixer according to the composition shown in Table 2, and kneading was performed for 10 seconds. Thereafter, water and an AE agent were added and kneaded for 90 seconds to obtain a ready-mixed concrete composition. The unit water amount was 171.7 liter / m ³ by subtracting 3.3 liter / m ³ which is the necessary water amount at the casting site. In addition, the addition amount of the AE agent is 0.0005% by mass in the following Examples 1 to 5, and 0.0005% by mass, 0.0003% by mass in the following Comparative Examples 1 to 3, respectively, with respect to the unit cement amount. 0.0005% by mass was added. In addition, for the comparative example, the addition amount was adjusted so as to have a predetermined air amount (4.5 ± 1.5% by mass). Further, the mixing of the hydraulic composition per batch was 40 liters.

<Material used>
(1) Cement Ordinary Portland cement manufactured by Taiheiyo Cement Co., Ltd. (density: 3.16 g / cm ³ )
(2) Fine aggregate sand having a maximum particle size of 5 mm, from Shimogarigawa, Myoko-shi, Niigata, water absorption: 2.29%, surface dry density: 2.57 g / cm ³ , coarse particle ratio: 2.81%
(3) Coarse aggregate Crushed stone having a maximum particle size of 25 mm, from Shimogarigawa, Myoko-shi, Niigata Water absorption: 2.05%, surface dry density: 2.61 g / cm ³ , coarse particle ratio: 6.62%
(4) AE agent; Master Air No. 775S
BASF Japan Co., Ltd., modified alkyl carboxylic acid compound-based anionic surfactant (5) Antifoaming agent; 404
BASF Japan Co., Ltd., polyalkylene glycol derivative (6) water (W)
Tap water

C. Preparation of hydraulic composition [Examples 1 to 5, Comparative Examples 1 to 3]
To the ready-mixed concrete composition obtained in Preparation Example B1, 3.3 L / m ^{3 of} each of the mixed aqueous solutions prepared in Preparation Examples A1 to A5 and Comparative Preparation Examples A1 and A2 was added, and the mixture was further kneaded for 90 seconds. Thus, a hydraulic composition was obtained.
In Examples 1 to 5, the content of the antifoaming agent in the aqueous solution of the admixture was 0.75% by mass in Examples 1 to 3 and 1 in Example 4, depending on the content of the water-soluble cellulose ether. 0.0% by mass, and 1.35% by mass in Example 5.

The following evaluation was performed about the obtained hydraulic composition. Table 3 shows the results.
<Evaluation method>
1. Temperature at which the hydraulic composition was kneaded The material temperature was adjusted so that the temperature at which the hydraulic composition was kneaded was 20 ± 3 ° C.
2. Air volume The test was performed according to JIS A1128.
3. Slump test A test was performed according to JIS A1101.
4. Bleeding rate The test was performed according to JIS A 1123.
The lower the bleeding rate, the better the material separation resistance.

As shown in Table 3, in Examples 1 to 5, the sodium ion concentration in the (A) mixed aqueous solution is high, and a higher concentration aqueous solution of cellulose ether can be obtained due to salting out. As a result, it can be seen that a predetermined amount (500 g / m ³ or more) of the water-soluble cellulose ether could be added at the casting site, and a hydraulic composition having a high bleeding reducing effect was obtained.
On the other hand, in Comparative Examples 1 and 2, since the concentration of the water-soluble cellulose ether in the mixed aqueous solution could not be increased, only 66 g / m ³ and 330 g / m ³ were substantially added to the water-soluble cellulose ether, respectively. It can be seen that the hydraulic composition was inferior in the bleeding reduction effect.
On the other hand, in Example 5 using sodium gluconate which is a setting retarder as an anionic substance, a significant effect of reducing the bleeding rate was obtained as compared with Comparative Example 3 in which no water-soluble cellulose ether was added. .

Claims (5)

(A) A water-soluble salt having a sodium ion concentration of 5,000 to 50,000 ppm selected from a water reducing agent and a setting retarder, and one or more water-soluble celluloses selected from hydroxypropylmethylcellulose and hydroxyethylmethylcellulose comprises ether and before and mixing an aqueous solution obtained by salting out the Kisui soluble cellulose ether, characterized by mixing (B) hydraulic substance, a ready-mixed concrete composition comprising aggregate and water, in striking設現field A method for producing a hydraulic composition. Manufacturing method of the preceding cinchona thorium ion concentration, 8,600 ~50,000ppm der Ru claim 1 hydraulic composition.   The method for producing a hydraulic composition according to claim 1 or 2, wherein the water reducing agent is a polycarboxylic acid-based water reducing agent.   3. The method for producing a hydraulic composition according to claim 1, wherein the setting retarder is sodium gluconate.   The method for producing a hydraulic composition according to any one of claims 1 to 4, wherein the water-soluble cellulose ether is hydroxypropyl methylcellulose.